Telecommunication networks transport voice and data according to a variety of standards and using a variety of technologies. Circuit-switch networks such as plain old telephone service (POTS) utilize transmission paths dedicated to specific users for the duration of a call and employ continuous, fixed-bandwidth transmission. Packet-switch networks (PSNs) allow dynamic bandwidth, depending on the application, and can be divided into connectionless networks with no dedicated paths and connection-oriented networks with virtual circuits having dedicated bandwidth along a predetermined path. Because packet-switched networks allow traffic from multiple users to share communication links, these networks utilize available bandwidth more efficiently than circuit-switched networks.
Internet protocol (IP) networks are connectionless packet-switched networks. IP networks transport information by breaking up bitstreams into addressable digital packets. Each IP packet includes source and destination addresses and can take any available route between the source and the destination. The IP packets are transmitted independently and then reassembled in the correct sequence at the destination.
Traditional IP networks employ synchronous optical network (SONET) or other time division multiplex (TDM) links that support only point-to-point connectivity across the network. Consequently, excessive channelization is required on physical ports of the IP network for point-to-multipoint data flows. This leads to greater cost in terms of support and equipment both in the network and in subtending network elements. In addition, the number of peering sessions required for subtending routers is significantly increased.